code: def _forward(self, inputs):
      (theta,) = inputs
      H, W = self.output_shape
      B, _, _ = theta.shape
      xp = backend.get_array_module(theta)
  
      ys, xs = xp.meshgrid(
          xp.linspace(-1, 1, H, dtype=theta.dtype),
          xp.linspace(-1, 1, W, dtype=theta.dtype),
          indexing="ij",
          copy=False,
      )
  
      coords = xp.concatenate(
          [xs[None], ys[None], xp.ones((1, H, W), dtype=theta.dtype)],
          axis=0,
      )
      grid = theta.dot(coords.reshape(3, H * W)).reshape(B, 2, H, W)
      return (grid,)
  
file_path: chainer/chainer/functions/array/spatial_transformer_grid.py
imports: import numpy
  import chainer
  from chainer import backend
  from chainer.backends import cuda
  from chainer import function
  from chainer.utils import argument
  from chainer.utils import type_check
label_desc: Use image node_id 5 for calling the SpatialTransformerGrid obj's underlying member method code with example usage: obj._forward(inputs) and returns: grid